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3W Bearcat with Moki 300

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3W Bearcat with Moki 300

Old 05-21-2015, 06:32 AM
  #76  
rbgetz
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The carb was flooding engine and fuel was coming out the choke.. I mean dripping heavy. I checked the pop-off needle (metering needle) and seemed to hold under pressure. I even turned the low needle completely closed just to do a quick test and the fuel still came out of the choke spilling into the fuse. I talked with Gotz and decided to just send back to him and he's having his "carb" guy fully test it. He still believes the metering spring is too weak to hold the pressure.
Old 05-21-2015, 10:54 AM
  #77  
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Rob,
The cockpit looks great. Can't wait to see it fly.

Steve
Old 05-30-2015, 02:29 PM
  #78  
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Well.. the Carb has been repaired and on its way back... In the meantime it's a cold, rainy, windy day here in Northern, Illinois, so I was able to work on the cockpit and finish it. A few snags but I really like the way it turned out.

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Old 06-10-2015, 04:08 PM
  #79  
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OK... I ended up replacing both the Carb and fuel pump. Much better results. Ran engine tonight and tuned a bit. I'm getting around 3650 RPM's. Idle seems to settle in nice around 900 RPM. Hopefully over the next few days I can go through the whole plane and get ready for Maiden. Here's the video.. sorry for the poor quality, but by myself and only phone video.

https://youtu.be/1SzebNtedd0
Old 06-11-2015, 12:28 PM
  #80  
Greg Wright
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Let me know when and where the Maiden will take place. I like to come and watch maybe..
Old 06-11-2015, 06:33 PM
  #81  
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Sounds good Greg.. I'll most likely be at Fox Valley Aero.
Old 06-23-2015, 08:10 AM
  #82  
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WelI figured out my engine flooding trouble and thought I'd share. I was getting flooded out before I even started the engine with the APS 380 fuel pump. I set up the pump exactly to what they had in the manual.. but what was happening is the return line from the pump connect via a T-connector to the fill-line for the tank. just as recommended. but what happened, is when I was filling my tank, fuel would flow backward down the Fuel Pump return-line and pushed fuel into the carb. So.. I was flooding before I even started. What I did to resolve is bought a fuel line check-value and placed on the return line from the pump, before the "T" on the fill line.. Engine starts and runs fine. I can't believe I haven't read about this in all the threads I've read.. Or.. I'm open to positive criticism if I'm miss something.. Always willing to learn.
Old 06-24-2015, 01:11 PM
  #83  
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The Bearcat is finally airworthy. We worked out some setup issues on the engine and had three successful flights on the bearcat today, thanks to the help from Greg Wright. Greg, I want to thank you for stopping out and helping tweak the plane and giving me some valuable pointers. Without it, I don't think the day would have gone well. I'm going to make some final adjustments as you suggested and make sure everything is screwed down. The weather looks good for the Windy City Warbird Event this weekend.

Steve's going to send me the video from one of the flights. I'll make sure to add to this thread.
Old 06-24-2015, 01:45 PM
  #84  
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Rob,

It was my pleasure to come out and help make your day a successful one. I hope you have many enjoyable flights with it.

Maybe one day when i have my wildcat finished we can do some more flying together. Hope you enjoy the weekend with it.
Old 06-25-2015, 04:47 AM
  #85  
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Rob and Greg,

This is a great thread I have been following for some time as I am about to finish a 3W Bearcat myself - with a Moki 250 though.
Although having heard a lot positive about the flight characteristics of this 3W bird, it could certainly support my maiden flight knowing of these valuable points you shared this day.
Would you mind sharing?
Thanks for a great thread and for sharing.

KR

Frode
Old 06-27-2015, 07:36 PM
  #86  
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Hello Frode,

I'll be happy to share my first experiences with the Bearcat. My first few take-offs were a little rough. I allowed the plane to lift off too quick and was close to stalling. Luckily the big 300 pulled it right through. I was amazed with the power the 300 has. It pulls that 53 lbs plane with no issues. Let it build up airspeed. Just make sure to ease the power during the take off roll. The engine will pull that plane left. Once in the air the plane was amazingly smooth. On my first pass I needed very little trim adjustments. Also, like many bigger heavier warbirds, I had to keep a little power in when coming in for landing on final until ready to touch down and cut the power to settle it in. Greg did a great job coaching me through the first 3 flights. MAKE SURE to strengthen the landing gear on those wings. That's one thing I've heard from a lot of people and broke my gear... Fixed, but it's just as important an issue as the talk about the 3W Bearcat and tail flutter. I had no tail flutter, but during the first flight I did experience aileron flutter and had to make a quick landing. It was my fault though, as we determined it was a loose control linkage. Make sure everything is tight. It almost cost me my plane. I can tell this is going to be my favorite plane for sometime. I added a video a friend took with his phone. Not great quality and I'll try to add more.
https://www.youtube.com/watch?v=AnTNdPuqE6Q&feature=youtu.be
Old 06-28-2015, 11:44 AM
  #87  
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Many thanks Rob.
This is for sure valuable points to keep in mind and I am happy all went well on your maiden.
What a great machine you have made and the power is just amazing. So nice to see her in flight.
Thanks for sharing and keep on enjoying. Reinforcement of the landing gear mounts was actually one of the first things I did starting on the build.
I know by experience that I do not always have these smooth landings and it is just so sad when the gears brake down on the first flights.
I will share some as well when moving on with my build.

KR
Frode
Old 08-18-2015, 06:05 AM
  #88  
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I may need some HELP! during the first maiden, I think I mentioned getting flutter in an aileron. This was due to a loose control arm.. since then, I've had many great flights on the Bearcat. However, during my last outing, I started up and was just warming the engine and testing the control surface prior to flight and noticed one aileron tilting a bit. I thought one of the bolts came loose, but one of the actual aileron hinges was broken.. If you have a 3W, you know these are made out of some type of phenolic material. it sheared right at the exit point from the wing. I can make a pattern to cut new ones, but not sure how to drill and tap out the old ones? has anyone had this type of repair. Trying to take the less evasive route of cutting open the whole wing. Any suggestion would be apprecaited. I'll take a photo tonight and attach.
Old 08-18-2015, 06:34 AM
  #89  
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I may be of some help with the aileron hinge. I had a dead stick and did a very poor job of not making it back to the field. Pilot error occurred when I left the gear down and ended up tearing up the wing at the retract area. I don't think the ailerons suffered any damage at all. Let me take a look. I can probably open up the wing and try to cut out one or two of those hinge points. Happy to mail them to you if you think you can use them. I can also take some pics of how they are installed for you with the wing cut open. Might save you some time cutting in the wrong place. I'll try to get to it today for you. I have a new wing "on the bench" but just haven't had the time to get to it.

Dave
Old 08-18-2015, 07:55 AM
  #90  
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Hi Dave! This might be very helpful. I had one hinge broken and a second one was just about to break off. Ordering new wings was around $500-$600 per wing and 6-8 week lead time. with just a few broken hinges, that doesn't make sense. I'm just trying to find best way to solve this. If you wouldn't mind taking a picture first, that would be helpful. I was going to cut some hinges out of fiberglass but aligning may be hard and not sure how the internal structure looks. Rob
Old 08-18-2015, 11:29 AM
  #91  
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Hey Rob,

I did a little surgery to see what was going on inside the wing. Basically the rear spar is blasa sandwiched with some type of glass material. This makes up the trailing edge of the wing. The hinges are mounted through that and glued into balsa blocks. Note that the blocks are not perfectly square with the hinge line. So I personally would tape off a square area around the hinge (on the bottom of the wing). Maybe 3 inches on either side of the hinge point to account for the offset internal block not being square on the hinge. Take a new, very sharp exacto blade and cut a hatch along the tape line using a metal ruler as a guide. When you are cutting back towards the trailing edge of the wing, it will stop approximately 20mm from the trailing edge where the rear spar is. Take the hatch off and you will have access to the hinge mounting block. Tear out the old one and insert a new block with the new hinge in it. You can then glue in 4 hard wood posts for the hatch that you cut out to mount back onto the wing with 4 small screws. I don't think you will even notice it other than seeing the small button head screws.

I can send you these hinges that I pulled out if you want them. They are still functional if you just drill out the glue where the holes were in the front and clean up the edges with a dremel or sharp knife. PM me your address and I'll send them to you. Let me know if you need any other pictures. I pulled the trigger on a new wing set. A little over $1600 shipped and the 4 weeks turned into over 8 months. Not Gerhards fault (he was great throughout the process) but it did take a long time for the factory to lay up a new set. Not worth it in your case. You should be able to replace these hinges in an evening or two no problem. I don't think you will even be able to tell you went into the wing when you are done with it.
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Old 08-18-2015, 04:28 PM
  #92  
rbgetz
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Hi Dave.. I really appreciate this. I'll send you a PM. rob
Old 08-21-2015, 12:28 PM
  #93  
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Really nice build you've got here. I'm definitely not a fan of the phenolic material as they only have strength in one direction. I've had my fair share of using a dremel to grind out and Hysol with new. How's the Moki 300 running? I've got one on an older Carf 3m Yak that's getting closer to maiden. Going a little different route by trying to magnify the sound. Should be interesting with smoke.
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Old 08-21-2015, 05:03 PM
  #94  
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Hey there 2Brave, I like the Moki on that air frame. I have to admit that's a clever exhaust. I've heard that flaring out the end of the exhaust and shorter create that deeper sound. I'd really like to hear the result of your beer cans.Those can are definitely flared out. The Moki 300 is running great once I figured out the particulars around it. It starts right after I choke it on the 3-4 flip. I'm having trouble restarting when hot, but once it sits for 15-20 after a flight, it starts right back up. Never stalled in the air so far.. knock on wood... With the help from Smurjet, looks like I should be able to fix that aileron on the Bearcat...Rob
Old 08-25-2015, 03:51 PM
  #95  
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New style hinge points. Definitely a different material and quite a bit thinner. Not nearly as stiff.
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Old 08-25-2015, 05:59 PM
  #96  
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Hey Dave, got the PM as well.. Wow, that's really interesting that 3W would go to a lesser quality on the aileron hinges. I have to assume that's the same for the flaps.. They really have a lot of play in them and I think that might have contributed to the aileron flutter I had on the first flight. I'm lucky on my other flights they didn't snap. Thanks again for sending me those stronger hinges. I'm going to use those, but now I'm worried about the other side. I think I'll try to stiffen the other side as well. Or could we be missing something and 3W wanted more play in them? It wouldn't make sense, but either does using lesser quality material in an expensive air frame.... rob
Old 08-25-2015, 08:02 PM
  #97  
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Did a rough runup at the field Sunday. Didn't have the fuel pump hooked up as you can hear in the video, need a 12 channel Rx to program it, but it actually sounded a bit more throaty. Will try again this wknd. Would love to have a 3W Bearcat to put it in. Awesome work you guys are doing.

http://youtu.be/CbJtHlPC1ZM
Old 08-26-2015, 09:59 AM
  #98  
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Hey 2Brave, It sounded deeper but it could also be running a little rich. not sure what prop size/pitch you used, but also remember once you add the fuel pump, that will create a richer mixture. were you able to grab peak RPM and idle RPM? If you read the Moki Care & Maintenance thread, they really have a lot of great info, mostly on the 250, but very similar operating procedures between them. When I added the fuel pump, my 300 ran really rich from the mfg settings and had to lean out quite a bit. I then had Greg Wright tweak even further at the field during some of the earlier test flights.
Old 08-26-2015, 11:31 AM
  #99  
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Last edited by Greg Wright; 08-26-2015 at 11:41 AM.
Old 08-30-2015, 05:18 PM
  #100  
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Thanks to Dave sending me his old hinges, I was able to fix the aileron. I used the Dremel bit #110 which is an engraving bit that can be used on fiberglass. without cutting open the whole wing, I was able to just route of the broken hinges and basically slide the new ones in an used BVM Aeropoxy. those things are in super strong and don't move at all. Then on the ones that we're not broken, I use 1/6" g10 fiberglass and made 1" X 2" plates to support the other hinges at their base. It definitely strengthen those up. You should be able to see that mods in the photos.. Thanks again SmurfJet. Hopefully i can get to the field this week to test fly.
https://www.youtube.com/watch?v=Vqn2slGDXlY&feature=youtu.be
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